Excess levels of ozone can be dangerous to the health of humans. As a result, there are strict regulations regarding human exposure to large doses of ozone. To warn the public of a high concentration of ozone in the atmosphere, ozone levels are monitored using ozone detectors. Current ozone detectors generally fall into three classes: detectors that operate based on ozone light absorption; detectors that operate based on semiconductor devices designed to sense ozone in air passed over the semiconductor device; and detectors that utilize electrochemical effects.
The detectors that operate based on ozone light absorption take advantage of the Beer-Lambert absorption law of ultraviolet (UV) light passing through ambient gas in a chamber that contains ozone. Since ozone strongly absorbs UV radiation, a concentration of ozone can be inferred from a measured amount of UV absorption. The Beer-Lambert law can be applied to calculate the ozone concentration based on the UV absorption detected using an optical source-detector couple. Typically, these devices utilize mercury discharge lamps, which necessitate relatively large detectors with lamps having a limited operational lifetime. Additionally, these devices typically require a chamber having a size in the tens of centimeters in order to successfully detect small levels of ozone.
The detectors that operate based on semiconductor devices designed to sense ozone in air passed over the semiconductor device have a high sensitivity not only to ozone, but other gases and trace elements present in the atmosphere, such as, for example, traces of organic compounds. Calibration of these detectors may be less effective as the devices age and/or interact with different environmental factors affecting an overall performance of the detector. The detectors that utilize electrochemical effects often cannot accurately register small levels of ozone concentration present in the atmosphere, which, nevertheless, can be hazardous to human health.